1. Field of the Invention
The present invention relates to the prevention of unwanted polymerization of monomers during storage, shipment, and manufacturing processes, and particularly to a method of inhibiting free radical polymerization of styrene.
2. Description of the Related Art
Styrene is a vinyl monomer. Various conditions may induce the formation of free radicals in styrene, thereby initiating chain polymerization. Typically, in the handling and storage of styrene monomer, the styrene temperature must be carefully controlled at around 10° C. to prevent styrene polymerization. In order to ensure purity, polymerization inhibitors are typically added to styrene monomers that are to be stored or shipped. In relatively hot climates, and during the transportation of the styrene, the initial inhibitor level is usually increased to avoid autocatalytic polymerization, which becomes self-sustaining above 20° C. Similarly, certain manufacturing processes that utilize styrene monomer may include processing the styrene at temperatures that induce the formation of radicals and unwanted chain growth polymerization of the styrene.
The inhibition of polymerization in styrene with carbonaceous nanomaterials is known, e.g., by p-tert-butylcatechol or by hydroquinone. However, the more of an inhibitor that is added to the styrene, the less pure the styrene becomes, and thus requires complicated filtration and purification processes before the styrene monomer can be used. A highly effective polymerization inhibitor requiring a minimal amount to be added to the styrene would be desirable.
Thus, a method of inhibiting free radical polymerization of styrene solving the aforementioned problems is desired.